need some help from those RAID experts

fatcat

So, I got one of these on black friday:

Rosewill RSV-S4-X 4 Bay SATA to eSATA (Port Multiplier) JBOD / RAID 0, 1, 1+0, 5 Enclosure

I plan to fill it with 4x1.5TB drives and use it for backup of my hard drives|SSD's etc. I assume I will want to use Raid 5 (confused what Raid 5+spare means on their website thou)

Now is this going to give me 6TB of backup space, or 4.5TB with one drive being used to keep the data info? I've only ever played with Raid 0 and 1 before. So, is Raid 5 the best option also?

info and opinions would be marvelous :thumbup

mertesn

RAID-5 stripes data and parity across all drives. Your capacity is 1.5TB * (n - 1), where n is the number of drives in the array. Having a hot spare just means you have a drive "separated" from the array waiting for one of the other drives to fail. Should be pretty unnecessary. With RAID-5 you can actually lose one drive and not lose your data - the parity data will allow you to rebuild your array and even continue to use your data until the drive can be replaced. Keep in mind that under these conditions you'd be running in a degraded state and losing another drive would result in a total loss of data.

That being said, four drives in RAID-5 would get you 4.5TB of useable storage. Three plus a hot spare would be 3TB.

And yes, RAID-5 would be your best option.

fatcat

thanks mert

I'm gonna assume the device(or Windows?) lets me know if one drive fails yes? And by fail, do you mean the "raid5" fails or the hard drive actually went bad? I've had Raid0 arrays go bad and both hard drives were perfectly fine.

And, one other thing I was thinking: any way to set it up where I have 4 hard drives show up as two hard drives (in windows) with a backup going to each hard drive?

or is raid5 still better?

mertesn

fatcat wrote:

thanks mert

I'm gonna assume the device(or Windows?) lets me know if one drive fails yes?

That should be the case, but without reading the manual I'm not sure.

fatcat wrote:

And by fail, do you mean the "raid5" fails or the hard drive actually went bad? I've had Raid0 arrays go bad and both hard drives were perfectly fine.

If a single drive in the array dies, you're still ok.

fatcat wrote:

And, one other thing I was thinking: any way to set it up where I have 4 hard drives show up as two hard drives (in windows) with a backup going to each hard drive?

or is raid5 still better?

That would be the 1 + 0 option. You could _potentially_ lose two drives and not be hosed (one drive from each mirrored pair), but the odds of this happening are pretty slim. I'd stick with RAID-5.

fatcat

sounds good!